US Patent 7089633 Side release buckle

A side release buckle is disclosed to have a center lock formed of a hooked portion at the free end of the center bar of the male buckle member and a hook hole in the bottom wall of the female buckle member to reinforce the strength of the connection between the locking bars of the male buckle member and the respective side notches of the female buckle member. The locking bars each have a wedge block for lifting the free end of the center bar to unlock the center lock when the user squeezed the locking bars inwards to disengage the locking bars from the side notches of the female buckle member.